Sweaty Swimming

by Nick Mitchell ‘04

Like most people, I have a desire to get my body in some sort of physical condition, to the point when I can look in the mirror and give a genuine rendition of “I’m too sexy for my shirt” instead of “I’ve got a lovely bunch of body fat”. Like most people, I try to exercise to achieve this end, and then a few weeks later, I try to exercise again. Unlike most people though, my attempts to turn feeble sinew into a Mr. Universe candidacy led me to solve one of the great mysteries of life.

It all started when my friend Andy and I decided to start swimming. This started when Andy and I stopped trying to lift weights, which had started when Andy and I had stopped trying to run. We like to think of it as making progress.

When Andy and I go swimming, we usually spend as much time in the locker room as we do in the pool. This is partly because a hot shower is much more attractive than a cold pool, and partly because while we change out of our wet trunks, Andy and I like to engage in philosophical conversation about girls, our bulging muscles, and the great mysteries of life.

Do you sweat when you swim?

During one such metaphysical discourse about how buff swimming was going to make us, we stumbled upon an intriguing question. Any seasoned exerciser like Andy or myself knows that one of the great advantages to swimming is that, when you’re done, you may be soaking wet— but not in the my-God-that’s-the-grossest-sweat-stain-I’ve-ever-seen kinda way.  Instead, you just reek of pleasant pool chemicals. Still, at least you don’t have to worry about sweat. Or do you?

Do you sweat when you swim? Andy maintained that of course you do— when you exercise, you sweat, period. But I was skeptical. You see, I knew that the purpose of perspiration was to lower your body temperature, which rises during periods of physical strain, like exercising. The sweat is secreted from glands in various areas of the body (in my case, every area of the body), and its evaporation draws heat away from your overheating exterior. But what if your body’s already immersed in cold water? What’s the point of sweating then? Surely, I thought, the body shows some discretion and won’t turn on the sweat switch unless your body is actually overheating.

Andy was swift to challenge my hypothesis. “What about when you run outside in the winter? Your body’s cold then, but you still sweat.” But I contended that this case is not the same at all, because presumably people run outside with clothes on, and this offers insulation from the cold air as well as preventing arrest. In addition, cold air would not have the same effect as cold water, because air is less dense and therefore steals away your heat at a slower rate. Imagine how unbearable the final scene in the Titanic would have been if they were beached on Antarctica instead!

I am never attempting to run naked through the chilly morning streets of Providence again. The police won't let me.

Still, Andy’s challenge gave me an idea for an experiment, a way to scientifically prove or disprove that we sweat when we swim. Since immersion in water confounded our ability to validate sweating or non-sweating, I would use air, and just make it significantly colder to compensate for the difference in densities. After some brief calculations (see Appendix A), I determined that the temperature of the air would need to be precisely 11.3 degrees Fahrenheit. Much to my joy, it was the coldest month of February that Providence had ever seen, and the next morning the Weather Channel reported 11 degrees. The clock in front of Fleet bank agreed—the experimental conditions were perfect.

According to the scientific method, an experiment must be repeated thoroughly to establish a consistent results. Unfortunately, with my experiment, this was impossible. I am never attempting to run naked through the chilly morning streets of Providence again. The police won’t let me.

So I turned a cold shoulder (among other things) to scientific ambition, and decided to conduct my next scientific search with Google. “Do you sweat when you swim?” The first page that comes up is about treating arthritic dogs. I bookmarked that one and moved on. It turned out there was remarkably little out there, which surprised me because of the magnitude of the question. Only the Australian Institute of Sports had realized its importance, and therefore conducted an extensive five-year study to solve this “great mystery of life.” (I’m not kidding, by the way, they really called it a “great mystery of life.” Right up there with “Is there a God?”, “Are humans naturally good?” and “How do they get the creamy filling inside a Twinkie?”)

Everything was accounted for; there was even a discreet method that swimming subjects could alert experimenters that their results had been marred by "unforeseen circumstances" while in the pool.

Their study was certainly more simplistic and less masochistic than my own.  The amount of sweat sweated was determined by weighing swimming subjects before and after their workout, and any other mass changes like drinking water or visiting the bathroom also involved a weigh-in. Everything was accounted for; there was even a discreet method that swimming subjects could alert experimenters that their results had been marred by “unforeseen circumstances” while in the pool.

After 295 observations, the results were in. Do you sweat when you swim? Sort of. Swimmers averaged a sweat rate of 123 milliliters per kilometer swum, but this number is significantly lower than average sweat rates for other types of exercise (about a third of the sweat rate for running and half that of cycling). So the answer to the burning question was yes and no; I had been both right and wrong. You do sweat when you swim, but because your body heat is conducted by colder pool water, you don’t sweat as much as you would exercising out of water.

For those of you engaged in a quest of physical perfecting similar to Andy’s and mine, the Australian study has vast implications. First of all, since you do sweat while swimming, during a longer workout it’s important to replenish your body fluids and avoid dehydration. How you do this is your own choice, but I would discourage drinking pool water, due to unforepeen circumstances. Secondly, put all your money on the Australian Swim Team in 2004—they’re going to drink up the competition.